US20120045170A1 - Optical waveguide for touch panel - Google Patents
Optical waveguide for touch panel Download PDFInfo
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- US20120045170A1 US20120045170A1 US13/207,926 US201113207926A US2012045170A1 US 20120045170 A1 US20120045170 A1 US 20120045170A1 US 201113207926 A US201113207926 A US 201113207926A US 2012045170 A1 US2012045170 A1 US 2012045170A1
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- light
- lens portion
- emitting
- receiving
- optical waveguide
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/042—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means
- G06F3/0421—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means by interrupting or reflecting a light beam, e.g. optical touch-screen
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/124—Geodesic lenses or integrated gratings
- G02B6/1245—Geodesic lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
- G02B6/138—Integrated optical circuits characterised by the manufacturing method by using polymerisation
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0412—Digitisers structurally integrated in a display
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12083—Constructional arrangements
- G02B2006/12102—Lens
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/30—Optical coupling means for use between fibre and thin-film device
Definitions
- the present invention relates to an optical waveguide for a touch panel which is used as a detection means for detecting a finger touch position and the like in a touch panel.
- a touch panel is an input device for operating an apparatus by directly touching a display screen of a liquid crystal display and the like with a finger, a purpose-built stylus and the like.
- the touch panel includes a display that displays operation details and the like, and a detection means that detects the position (coordinates) of a portion of the display screen of the display touched with the finger and the like.
- Information indicating the touch position detected by the detection means is sent in the form of a signal to the apparatus, which in turn performs an operation and the like displayed on the touch position.
- Examples of the apparatus employing such a touch panel include ATMs in banking facilities, ticket vending machines in stations, and portable game machines.
- the touch panel includes a light-emitting optical waveguide A 0 provided on one side of a display screen of a display 61 of a rectangular plan configuration, and a light-receiving optical waveguide B 0 provided on the other side of the display screen of the display 61 .
- a light-emitting element (not shown) is connected to the light-emitting optical waveguide A 0
- a light-receiving element (not shown) is connected to the light-receiving optical waveguide B 0 .
- the light-emitting optical waveguide A 0 divides a light beam emitted from the light-emitting element into multiple light beams.
- the optical waveguide A 0 includes a light-emitting section which emits the multiple light beams S 0 parallel to the display screen of the display 61 toward the other side of the display screen.
- the light-receiving optical waveguide B 0 includes a light-receiving section which receives the emitted light beams S 0 .
- optical waveguides A 0 and B 0 cause the emitted light beams S 0 to travel in a lattice form on the display screen of the display 61 .
- the finger blocks some of the emitted light beams S 0 .
- the light-receiving element connected to the light-receiving optical waveguide B 0 senses a light blocked portion to thereby detect the position (coordinates) of the portion touched with the finger.
- the light beams S 0 emitted from the light-emitting section of the light-emitting optical waveguide A 0 are restrained from diffusing (diverging) along a plane perpendicular to the display screen of the display 61 (in a vertical direction) by a lens portion 70 A provided in the light-emitting section to become parallel light beams.
- the reference numeral 72 designates an under cladding layer
- 73 designates cores
- 74 designates an over cladding layer.
- the touch panel including the optical waveguides A 0 and B 0 has failed to detect the finger touch position and the like in some instances. Warpage or distortion in locations where the optical waveguides A 0 and B 0 are provided results in warpage or distortion in the optical waveguides A 0 and B 0 themselves, which in turn prevents the light beams S 0 emitted from the light-emitting optical waveguide A 0 from entering the light-receiving optical waveguide B 0 .
- the touch panel including the optical waveguides A 0 and B 0 still has room for improvement in this regard.
- An optical waveguide for a touch panel is provided which is capable of causing light beams emitted from a light-emitting optical waveguide section to enter a light-receiving optical waveguide section even when warpage or distortion occurs in the optical waveguide itself.
- the optical waveguide for a touch panel comprises: cores; and an over cladding layer provided to cover the cores, the optical waveguide being provided along the periphery of a display screen of a display of a touch panel, the cores including a light-emitting core for emitting a light beam and a light-receiving core for receiving the light beam, the light-emitting core having an end surface positioned on one side of the display screen of the display, the light-receiving core having an end surface positioned on the other side of the display screen of the display, the over cladding layer including a first edge covering the end surface of the light-emitting core and configured in the form of a light-emitting lens portion having an outwardly-bulging arcuately curved surface as seen in vertical sectional view, and a second edge covering the end surface of the light-receiving core and configured in the form of a light-receiving lens portion having an outwardly-bulging arcuately curved surface as seen in vertical
- the optical waveguide is designed so that a light beam emitted from the light-emitting lens portion is diffused (diverged) in the direction of the height of the light-emitting lens portion or so that the height of the light-emitting lens portion is less than that of the light-receiving lens portion (in other words, so that the height of the light-receiving lens portion is greater than that of the light-emitting lens portion).
- the optical waveguide enables the light-receiving lens portion to lie within a light-receiving region, thereby causing the light beam emitted from the light-emitting lens portion to enter the light-receiving lens portion.
- the optical waveguide is capable of causing a light beam emitted from the light-emitting lens portion to enter the light-receiving lens portion when neither the warpage nor the distortion occurs.
- the first configuration of the light-emitting lens portion satisfies
- H 1 is the height of the light-emitting lens portion in millimeters
- H 2 is the height of the light-receiving lens portion in millimeters
- L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters
- M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters.
- the light beam emitted from the light-emitting lens portion is adapted to diffuse in the direction of the height of the light-emitting lens portion so that the vertical width (M) of the light beam is greater than 1.0 times the height (H 1 ) of the light-emitting lens portion and is not greater than 1.5 times the height (H 1 ) as measured at a position spaced a distance of ten times the height (H 1 ) apart from the edge of the light-emitting lens portion, for example.
- the vertical width (M) of the light beam is optimized while warpage or distortion is accommodated.
- the second configuration of the light-emitting lens portion satisfies
- H 2 H 1 ⁇ (1 +a ⁇ L/ 100)
- H 1 is the height of the light-emitting lens portion in millimeters
- H 2 is the height of the light-receiving lens portion in millimeters
- L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters
- M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters.
- the height (H 2 ) of the light-receiving lens portion is greater than the height (H 1 ) of the light-emitting lens portion so as to be greater than 1.0 times the height (H 1 ) and to be not greater than 1.5 times the height (H 1 ).
- the height (H 2 ) of the light-receiving lens portion is optimized while warpage or distortion is accommodated.
- the vertical width of a light beam emitted from the light-emitting lens portion is set in consideration for a distance from a light-emitting surface of the light-emitting core to the edge of the light-emitting lens portion, and the radius of curvature of the arcuately curved surface of the light-emitting lens portion. In this case, the optimization of the vertical width of the light beam is achieved more easily.
- FIG. 1A is a plan view schematically showing an optical waveguide for a touch panel according to a first preferred embodiment.
- FIG. 1B is a view, on an enlarged scale, schematically showing an end portion of a core enclosed within a circle E of FIG. 1A .
- FIG. 1C is a schematic sectional view, on an enlarged scale, taken along the line X-X of FIG. 1A .
- FIG. 2 is a perspective view schematically showing a touch panel including the optical waveguide.
- FIGS. 3A to 3D and FIGS. 4A to 4C are views schematically illustrating a method of manufacturing the optical waveguide.
- FIG. 5 is a sectional view schematically showing an optical waveguide for a touch panel according to a second preferred embodiment.
- FIG. 6 is a sectional view schematically showing a conventional touch panel.
- FIGS. 1A to 1C show an optical waveguide W 1 for a touch panel according to a first preferred embodiment.
- the optical waveguide W 1 according to the first preferred embodiment is in the form of a rectangular frame as seen in plan view.
- One L-shaped section constituting the rectangular frame is a light-emitting optical waveguide section A
- the other L-shaped section is a light-receiving optical waveguide section B.
- the optical waveguide W 1 includes an under cladding layer 2 in the form of a rectangular frame, and a plurality of cores 3 A and 3 B serving as a passageway for light and provided on predetermined portions of a surface of the under cladding layer 2 .
- the cores 3 A and 3 B are patterned to extend from predetermined portions F and G provided at outer end edges of the respective L-shaped sections to inner end edges of the respective L-shaped sections (on a display screen side of a display 11 with reference to FIG. 2 ) and to be arranged in a parallel, equally spaced relationship.
- the number of cores 3 A provided in the light-emitting optical waveguide section A is equal to the number of cores 3 B provided in the light-receiving optical waveguide section B. End surfaces at ends of the light-emitting cores 3 A respectively are in face-to-face relationship with end surfaces at ends of the light-receiving cores 3 B.
- the cores 3 A and 3 B are indicated by broken lines, and the thickness of the broken lines indicates the thickness of the cores 3 A and 3 B.
- the number of cores 3 A and 3 B are shown as abbreviated.
- FIG. 1B is an enlarged view of a portion enclosed with a circle E of FIG. 1A
- FIG. 1C is an enlarged sectional view taken along the line X-X of FIG. 1A
- an over cladding layer 4 is provided on the surface of the under cladding layer 2 so as to cover the cores 3 A and 3 B.
- edges of the over cladding layer 4 are extended to form lens portions 40 A and 40 B which cover the end surfaces of the light-emitting and light-receiving cores 3 A and 3 B lying at inner end edges of the L-shaped sections.
- the light-emitting lens portion 40 A and the light-receiving lens portion 40 B are equal in height, and are sized to be equal to the thickness of the over cladding layer 4 .
- the lens portions 40 A and 40 B have respective lens surfaces 41 A and 41 B that are arcuately curved surface as seen in vertical sectional view (with reference to FIG. 1C ).
- These light-emitting and light-receiving components i.e., the cores 3 A and 3 B, and the lens portions 40 A and 40 B, which are identical in structure with each other, are shown by the same drawing in FIG. 1B .
- a light beam S emitted from the light-emitting lens portion 40 A is adapted to diffuse (diverge) gradually in the direction of the height of the lens portion 40 A (in a vertical direction) as the light beam S travels, as shown in FIG. 1C .
- the vertical width of the light beam S satisfies the following relations (1) to (3).
- H 1 is the height of the light-emitting lens portion 40 A in millimeters
- H 2 is the height of the light-receiving lens portion 40 B in millimeters
- L is a distance between edges of the light-emitting and light-receiving lens portions 40 A and 40 B in millimeters
- M is a vertical width of a light beam S emitted from the light-emitting lens portion 40 A as measured at the edge of the light-receiving lens portion 40 B in millimeters.
- the light beam S emitted from the light-emitting lens portion 40 A is preferably adapted to diffuse in the direction of the height of the lens portion 40 A so that the vertical width M of the light beam S is greater than 1.0 times the height H 1 of the lens portion 40 A and is not greater than 1.5 times the height H 1 as measured at a position spaced a distance of ten times the height H 1 apart from the edge of the lens portion 40 A, for example.
- the diffusion (divergence) of the light beam S is set by adjusting a distance d from a light-emitting surface of a light-emitting core 3 A to the edge of the light-emitting lens portion 40 A, and the radius of curvature R of the curved lens surface 41 A of the light-emitting lens portion 40 A as appropriate.
- the emitted light beams S are diffused in the vertical direction. This accommodates warpage or distortion, if any, in the optical waveguide W 1 to achieve proper optical transmission.
- the emitted light beam S in the first preferred embodiment is diffused also in a horizontal direction (in a direction perpendicular to the height or vertical direction).
- the optical waveguide W 1 in the form of the rectangular frame is provided along the rectangular shape of the periphery of the display screen of the rectangular display 11 of a touch panel 10 so as to surround the display screen of the rectangular display 11 .
- a light source (not shown) such as a light-emitting element is connected to ends of the cores 3 A.
- a detector (not shown) such as a light-receiving element is connected to ends of the cores 3 B.
- the cores 3 A and 3 B are indicated by broken lines, and the thickness of the broken lines indicates the thickness of the cores 3 A and 3 B in a manner similar to that in FIG. 1A . Also, the number of cores 3 A and 3 B are shown as abbreviated. Only some of the multiple light beams S are shown in FIG. 2 for ease of understanding.
- light beams S emitted from the light source travel through the cores 3 A, and exit the end surfaces of the cores 3 A. Thereafter, the light beams S pass through and exit the lens portion 40 A at the edge of the over cladding layer 4 in front of the end surfaces of the cores 3 A. At this time, the diffusion of the light beams S in the vertical direction is optimized as described above by refraction resulting from the lens surface 41 A (with reference to FIG. 1C ) of the lens portion 40 A. Then, the light beams S travel over the display screen of the display 11 (with reference to FIG. 2 ) toward the light-receiving optical waveguide section B.
- the light beams S having traveled over the display screen of the display 11 enter the lens surface 41 B (with reference to FIG. 1C ) of the lens portion 40 B at the edge of the over cladding layer 4 , and are narrowed down and converged in the vertical direction by refraction resulting from the lens surface 41 B of the lens portion 40 B. Then, while being converged, the light beams S travel from the end surfaces of the cores 3 B into the cores 3 B, and are detected by the detector (not shown).
- Such transmission of the light beams S is done in the optical waveguide W 1 shown in FIG. 2 .
- the light beams S diffuse gradually in the vertical direction (upwardly as seen in FIG. 2 ) over the display screen of the display 11 of the touch panel 10 as the light beams S travel from the light-emitting optical waveguide section A toward the light-receiving optical waveguide section B.
- the light beams S travel in a lattice form (although only some of the light beams S forming the lattice are shown in FIG. 2 for ease of understanding).
- This enables the light-receiving lens portion 40 B to lie within a light-receiving region if warpage or distortion occurs in the optical waveguide W 1 .
- the position of the portion touched with the finger is accurately detected.
- FIGS. 3A to 3D and FIGS. 4A to 4C which mainly illustrate the opposed lens portions 40 A and 40 B shown in FIGS. 1A to 1C and a peripheral portion thereof.
- a base 1 of a flat shape (with reference to FIG. 3A ) for use in the manufacture of the optical waveguide W 1 is prepared.
- Examples of a material for the formation of the base 1 include glass, quartz, silicon, resin, and metal.
- the base 1 has a thickness, for example, in the range of 20 ⁇ m to 5 mm.
- the under cladding layer 2 is formed on a surface of the base 1 .
- a material for the formation of the under cladding layer 2 include thermosetting resins and photosensitive resins.
- thermosetting resins a varnish prepared by dissolving the thermosetting resin in a solvent is applied to the base 1 , and a layer of the applied varnish is then heated to thereby form the under cladding layer 2 .
- photosensitive resin a varnish prepared by dissolving the photosensitive resin in a solvent is applied to the base 1 , and a layer of the applied varnish is then exposed to irradiation light such as ultraviolet light to thereby form the under cladding layer 2 .
- the under cladding layer 2 has a thickness, for example, in the range of 5 to 70 ⁇ m.
- the cores 3 A and 3 B having a predetermined pattern are formed on a surface of the under cladding layer 2 by a photolithographic method.
- a photosensitive resin excellent in patterning characteristics is used as a material for the formation of the cores 3 A and 3 B.
- the photosensitive resin include UV-curable acrylic resins and UV-curable epoxy resins. These resins are used either singly or in combination.
- the sectional configuration of the cores 3 A and 3 B include a trapezoid and a rectangle having excellent patterning characteristics.
- the cores 3 A and 3 B have a width, for example, in the range of 10 to 100 ⁇ m, and a thickness (height), for example, in the range of 25 to 100 ⁇ m.
- the material for the formation of the cores 3 A and 3 B used herein has a refractive index higher than that of the material for the formation of the under cladding layer 2 described above and the over cladding layer 4 to be described below (with reference to FIG. 1C ).
- the adjustment of the refractive index may be made, for example, by adjusting the selection of the types of the materials for the formation of the under cladding layer 2 , the cores 3 A and 3 B and the over cladding layer 4 , and the composition ratio thereof.
- a photosensitive resin to be formed into the over cladding layer 4 is applied to the surface of the under cladding layer 2 so as to cover the cores 3 A and 3 B to form a photosensitive resin layer 4 a (uncured).
- An example of the photosensitive resin to be formed into the over cladding layer 4 includes a photosensitive resin similar to that for the under cladding layer 2 .
- a mold 20 for press molding the over cladding layer 4 into the shape of the rectangular frame is prepared.
- This mold 20 is made of a material (for example, quartz) permeable to irradiation light such as ultraviolet light, and includes a cavity having a mold surface 21 complementary in shape to the surface of the over cladding layer 4 including the lens portions 40 A and 40 B.
- the mold 20 is pressed against the photosensitive resin layer 4 a so that the mold surface 21 (the cavity) of the mold 20 is positioned in a predetermined location relative to the cores 3 A and 3 B, to mold the photosensitive resin layer 4 a into the shape of the over cladding layer 4 .
- the photosensitive resin layer 4 a is exposed to irradiation light such as ultraviolet light through the mold 20 in that state. Thereafter, a heating treatment is performed. The exposure and the heating treatment are carried out in a manner similar to those performed in the method for the formation of the under cladding layer 2 described with reference to FIG. 3A .
- the over cladding layer 4 in the form of a rectangular frame which includes the lens portions 40 A and 40 B.
- the over cladding layer 4 has a thickness (as measured from the surface of the under cladding layer 2 ) generally in the range of 50 to 2000 ⁇ m.
- the under cladding layer 2 together with the base 1 is cut into the shape of a rectangular frame by punching using a blade and the like.
- the optical waveguide W 1 in the form of the rectangular frame which includes the under cladding layer 2 , the cores 3 A and 3 B, and the over cladding layer 4 is manufactured on the surface of the base 1 .
- the optical waveguide W 1 is used after being stripped from the base 1 (with reference to FIG. 1C ).
- FIG. 5 shows an optical waveguide W 2 for a touch panel according to a second preferred embodiment.
- the height H 2 of the light-receiving lens portion 40 B is greater than the height H 1 of the light-emitting lens portion 40 A.
- a light beam S emitted from the light-emitting lens portion 40 A is adapted to be collimated, as shown in FIG. 5 , rather than to diffuse in the vertical direction. It should be noted that the emitted light beam S in the second preferred embodiment is diffused in a horizontal direction (in a direction perpendicular to the height or vertical direction). Other parts of the second preferred embodiment are similar to those of the first preferred embodiment. Like reference numerals and characters are used to designate parts similar to those of the first preferred embodiment.
- the height H 2 of the light-receiving lens portion 40 B satisfies the following relations (4) to (6).
- H 2 H 1 ⁇ (1 +a ⁇ L/ 100) (4)
- H 1 and H 2 are in millimeters
- L is a distance between edges of the light-emitting and light-receiving lens portions 40 A and 40 B in millimeters
- M is a vertical width of a light beam S emitted from the light-emitting lens portion 40 A as measured at the edge of the light-receiving lens portion 40 B in millimeters.
- the height H 2 of the light-receiving lens portion 40 B is preferably greater than the height H 1 of the light-emitting lens portion 40 A so as to be greater than 1.0 times the height H 1 and to be not greater than 1.5 times the height H 1 .
- light beams S emitted from the lens portion 40 A of the light-emitting optical waveguide section A are not diffused in the vertical direction but are collimated by refraction resulting from the lens surface 41 A of the lens portion 40 A.
- the height H 2 of the light-receiving lens portion 40 B is greater than the height H 1 of the light-emitting lens portion 40 A (the vertical width M of the collimated light beam S). This enables the light-receiving lens portion 40 B to lie within the light-receiving region if warpage or distortion occurs in the optical waveguide W 2 .
- the position of a portion of the display screen of the display 11 touched with a finger is accurately detected in the touch panel 10 (with reference to FIG. 2 ).
- the photosensitive resin is used to form the under cladding layer 2 .
- a resin film functioning as the under cladding layer 2 may be prepared and used as it is as the under cladding layer 2 .
- a substrate with a metal film formed on the surface thereof may be used as a body having a surface on which the cores 3 A and 3 B are to be formed.
- each of the optical waveguides W 1 and W 2 in the form of the rectangular frame may be divided into the two L-shaped optical waveguide sections constituting each of the optical waveguides W 1 and W 2 .
- a manufacturing method thereof may include the step of cutting the under cladding layer 2 together with the base 1 into two L-shaped sections in place of the step of cutting the under cladding layer 2 together with the base 1 into the shape of the rectangular frame. Further, at least one of the two L-shaped optical waveguide sections may be subdivided into linear optical waveguide sections constituting the at least one section.
- optical waveguides W 1 and W 2 in the first and second preferred embodiments are used after being stripped from the base 1 .
- the optical waveguides W 1 and W 2 still provided on the surface of the base 1 may be used without being stripped therefrom.
- a ray tracing simulation was performed using optical simulation software known as “LIGHTTOOLS” available from Optical Research Associates. Settings of a simulation model of a light-emitting optical waveguide section were as follows:
- Over cladding layer a refractive index of 1.50; a thickness of 1 mm; and a lens portion height of 1 mm.
- Cores a refractive index of 1.57; a thickness of 50 ⁇ m; and a width of 15 ⁇ m.
- Under cladding layer a refractive index of 1.50; and a thickness of 15 ⁇ m.
- a light-receiving surface (having a height of 1 mm and a width of 20 mm) corresponding to a light-receiving lens portion was set at a position 100 mm ahead of the edge of the lens portion in the simulation model.
- the optical transmission loss at the light-receiving surface was simulated, while the lens portion in the simulation model was inclined upwardly and downwardly with respect to a horizontal direction (with an inclination angle of 0 degrees).
- the lens portion was inclined upwardly and downwardly to an angle of six degrees in steps of one degree.
- the simulation model was held in a horizontal position. In this state, the optical transmission loss at the light-receiving surface was simulated, while the light-receiving surface was moved upwardly. The light-receiving surface was moved upwardly to a distance of 1.0 mm in steps of 0.2 mm.
- an optical waveguide for a touch panel in which emitted light beams are diffused in the vertical direction is capable of causing light beams emitted from the light-emitting lens portion to sufficiently enter a light-receiving optical waveguide section if warpage or distortion occurs in the optical waveguide itself.
- the simulation model in Sample 1 in which the emitted light beams were collimated light beams was held in a horizontal position, and the light-receiving surface was moved 0.1 mm upwardly.
- the illuminance of light beams received by the light-receiving surface was simulated, while the height (vertical width) of the light-receiving surface was increased from 1.0 mm to 2.0 mm in steps of 0.2 mm.
- the light-receiving surface was moved 0.1 mm downwardly.
- the illuminance of light beams received by the light-receiving surface was simulated, while the height of the light-receiving surface was increased in a similar manner.
- an optical waveguide for a touch panel in which the height of the light-receiving lens portion is greater than that of the light-emitting lens portion is capable of causing light beams emitted from the light-emitting lens portion to sufficiently enter the light-receiving optical waveguide section if warpage or distortion occurs in the optical waveguide itself.
- the optical waveguide for a touch panel is applicable to an optical waveguide for use as a detection means (a position sensor) for detecting a finger touch position and the like in a touch panel.
Abstract
An optical waveguide for a touch panel is capable of causing light beams emitted from a light-emitting optical waveguide section to enter a light-receiving optical waveguide section even when warpage or distortion occurs. Edges of an over cladding layer covering an end surface of a core for emitting a light beams and an end surface of a core for receiving the light beams respectively are configured in the form of light-emitting and light-receiving lens portions each having an outwardly-bulging arcuately curved surface as seen in vertical sectional view. The light-emitting lens portion has one of the following configurations: a configuration in which a light beam emitted from the light-emitting lens portion is adapted to diffuse in the direction of the height of the light-emitting lens portion; and a configuration in which the height of the light-emitting lens portion is less than that of the light-receiving lens portion.
Description
- 1. Field of the Invention
- The present invention relates to an optical waveguide for a touch panel which is used as a detection means for detecting a finger touch position and the like in a touch panel.
- 2. Description of the Related Art
- A touch panel is an input device for operating an apparatus by directly touching a display screen of a liquid crystal display and the like with a finger, a purpose-built stylus and the like. The touch panel includes a display that displays operation details and the like, and a detection means that detects the position (coordinates) of a portion of the display screen of the display touched with the finger and the like. Information indicating the touch position detected by the detection means is sent in the form of a signal to the apparatus, which in turn performs an operation and the like displayed on the touch position. Examples of the apparatus employing such a touch panel include ATMs in banking facilities, ticket vending machines in stations, and portable game machines.
- A detection means employing optical waveguides has been proposed as the detection means that detects the finger touch position and the like in the aforementioned touch panel, as disclosed in, for example, Japanese Published Patent Application No. 2010-15247. Specifically, as shown in
FIG. 6 , the touch panel includes a light-emitting optical waveguide A0 provided on one side of a display screen of adisplay 61 of a rectangular plan configuration, and a light-receiving optical waveguide B0 provided on the other side of the display screen of thedisplay 61. A light-emitting element (not shown) is connected to the light-emitting optical waveguide A0, and a light-receiving element (not shown) is connected to the light-receiving optical waveguide B0. The light-emitting optical waveguide A0 divides a light beam emitted from the light-emitting element into multiple light beams. The optical waveguide A0 includes a light-emitting section which emits the multiple light beams S0 parallel to the display screen of thedisplay 61 toward the other side of the display screen. The light-receiving optical waveguide B0 includes a light-receiving section which receives the emitted light beams S0. These optical waveguides A0 and B0 cause the emitted light beams S0 to travel in a lattice form on the display screen of thedisplay 61. When a portion of the display screen of thedisplay 61 is touched with a finger in this state, the finger blocks some of the emitted light beams S0. The light-receiving element connected to the light-receiving optical waveguide B0 senses a light blocked portion to thereby detect the position (coordinates) of the portion touched with the finger. It should be noted that the light beams S0 emitted from the light-emitting section of the light-emitting optical waveguide A0 are restrained from diffusing (diverging) along a plane perpendicular to the display screen of the display 61 (in a vertical direction) by alens portion 70A provided in the light-emitting section to become parallel light beams. InFIG. 6 , the reference numeral 72 designates an under cladding layer, 73 designates cores, and 74 designates an over cladding layer. - The touch panel including the optical waveguides A0 and B0, however, has failed to detect the finger touch position and the like in some instances. Warpage or distortion in locations where the optical waveguides A0 and B0 are provided results in warpage or distortion in the optical waveguides A0 and B0 themselves, which in turn prevents the light beams S0 emitted from the light-emitting optical waveguide A0 from entering the light-receiving optical waveguide B0. The touch panel including the optical waveguides A0 and B0 still has room for improvement in this regard.
- An optical waveguide for a touch panel is provided which is capable of causing light beams emitted from a light-emitting optical waveguide section to enter a light-receiving optical waveguide section even when warpage or distortion occurs in the optical waveguide itself.
- The optical waveguide for a touch panel comprises: cores; and an over cladding layer provided to cover the cores, the optical waveguide being provided along the periphery of a display screen of a display of a touch panel, the cores including a light-emitting core for emitting a light beam and a light-receiving core for receiving the light beam, the light-emitting core having an end surface positioned on one side of the display screen of the display, the light-receiving core having an end surface positioned on the other side of the display screen of the display, the over cladding layer including a first edge covering the end surface of the light-emitting core and configured in the form of a light-emitting lens portion having an outwardly-bulging arcuately curved surface as seen in vertical sectional view, and a second edge covering the end surface of the light-receiving core and configured in the form of a light-receiving lens portion having an outwardly-bulging arcuately curved surface as seen in vertical sectional view, the light-emitting lens portion having one of the following configurations: a first configuration in which a light beam emitted from the light-emitting lens portion is adapted to diffuse in the direction of the height of the light-emitting lens portion; and a second configuration in which the height of the light-emitting lens portion is less than that of the light-receiving lens portion.
- The optical waveguide is designed so that a light beam emitted from the light-emitting lens portion is diffused (diverged) in the direction of the height of the light-emitting lens portion or so that the height of the light-emitting lens portion is less than that of the light-receiving lens portion (in other words, so that the height of the light-receiving lens portion is greater than that of the light-emitting lens portion). Thus, if warpage or distortion occurs in the optical waveguide itself, the optical waveguide enables the light-receiving lens portion to lie within a light-receiving region, thereby causing the light beam emitted from the light-emitting lens portion to enter the light-receiving lens portion. Of course, the optical waveguide is capable of causing a light beam emitted from the light-emitting lens portion to enter the light-receiving lens portion when neither the warpage nor the distortion occurs.
- Preferably, the first configuration of the light-emitting lens portion satisfies
-
M=H1×(1+a×L/100) -
0<a≦5 -
H1=H2 - where H1 is the height of the light-emitting lens portion in millimeters, H2 is the height of the light-receiving lens portion in millimeters, L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters, and M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters. In this case, the light beam emitted from the light-emitting lens portion is adapted to diffuse in the direction of the height of the light-emitting lens portion so that the vertical width (M) of the light beam is greater than 1.0 times the height (H1) of the light-emitting lens portion and is not greater than 1.5 times the height (H1) as measured at a position spaced a distance of ten times the height (H1) apart from the edge of the light-emitting lens portion, for example. The vertical width (M) of the light beam is optimized while warpage or distortion is accommodated.
- Preferably, the second configuration of the light-emitting lens portion satisfies
-
H2=H1×(1+a×L/100) -
0<a≦5 -
H1=M - where H1 is the height of the light-emitting lens portion in millimeters, H2 is the height of the light-receiving lens portion in millimeters, L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters, and M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters. In this case, for example, when the distance (L) between the edges of the light-emitting and light-receiving lens portions is ten times the height (H1) of the light-emitting lens portion, the height (H2) of the light-receiving lens portion is greater than the height (H1) of the light-emitting lens portion so as to be greater than 1.0 times the height (H1) and to be not greater than 1.5 times the height (H1). The height (H2) of the light-receiving lens portion is optimized while warpage or distortion is accommodated.
- Preferably, the vertical width of a light beam emitted from the light-emitting lens portion is set in consideration for a distance from a light-emitting surface of the light-emitting core to the edge of the light-emitting lens portion, and the radius of curvature of the arcuately curved surface of the light-emitting lens portion. In this case, the optimization of the vertical width of the light beam is achieved more easily.
-
FIG. 1A is a plan view schematically showing an optical waveguide for a touch panel according to a first preferred embodiment. -
FIG. 1B is a view, on an enlarged scale, schematically showing an end portion of a core enclosed within a circle E ofFIG. 1A . -
FIG. 1C is a schematic sectional view, on an enlarged scale, taken along the line X-X ofFIG. 1A . -
FIG. 2 is a perspective view schematically showing a touch panel including the optical waveguide. -
FIGS. 3A to 3D andFIGS. 4A to 4C are views schematically illustrating a method of manufacturing the optical waveguide. -
FIG. 5 is a sectional view schematically showing an optical waveguide for a touch panel according to a second preferred embodiment. -
FIG. 6 is a sectional view schematically showing a conventional touch panel. - Preferred embodiments according to the present invention will now be described in detail with reference to the drawings.
-
FIGS. 1A to 1C show an optical waveguide W1 for a touch panel according to a first preferred embodiment. As shown inFIG. 1A , the optical waveguide W1 according to the first preferred embodiment is in the form of a rectangular frame as seen in plan view. One L-shaped section constituting the rectangular frame is a light-emitting optical waveguide section A, and the other L-shaped section is a light-receiving optical waveguide section B. The optical waveguide W1 includes an undercladding layer 2 in the form of a rectangular frame, and a plurality ofcores under cladding layer 2. Thecores display 11 with reference toFIG. 2 ) and to be arranged in a parallel, equally spaced relationship. The number ofcores 3A provided in the light-emitting optical waveguide section A is equal to the number ofcores 3B provided in the light-receiving optical waveguide section B. End surfaces at ends of the light-emittingcores 3A respectively are in face-to-face relationship with end surfaces at ends of the light-receivingcores 3B. InFIG. 1A , thecores cores cores -
FIG. 1B is an enlarged view of a portion enclosed with a circle E ofFIG. 1A , andFIG. 1C is an enlarged sectional view taken along the line X-X ofFIG. 1A . As shown inFIGS. 1B and 1C , an overcladding layer 4 is provided on the surface of theunder cladding layer 2 so as to cover thecores cladding layer 4 are extended to formlens portions cores lens portion 40A and the light-receivinglens portion 40B are equal in height, and are sized to be equal to the thickness of the overcladding layer 4. Thelens portions respective lens surfaces FIG. 1C ). These light-emitting and light-receiving components (i.e., thecores lens portions FIG. 1B . - A light beam S emitted from the light-emitting
lens portion 40A is adapted to diffuse (diverge) gradually in the direction of the height of thelens portion 40A (in a vertical direction) as the light beam S travels, as shown inFIG. 1C . Preferably, the vertical width of the light beam S satisfies the following relations (1) to (3). -
M=H1×(1+a×L/100) (1) -
0<a≦5 (2) -
H1=H2 (3) - where H1 is the height of the light-emitting
lens portion 40A in millimeters, H2 is the height of the light-receivinglens portion 40B in millimeters, L is a distance between edges of the light-emitting and light-receivinglens portions lens portion 40A as measured at the edge of the light-receivinglens portion 40B in millimeters. Specifically, the light beam S emitted from the light-emittinglens portion 40A is preferably adapted to diffuse in the direction of the height of thelens portion 40A so that the vertical width M of the light beam S is greater than 1.0 times the height H1 of thelens portion 40A and is not greater than 1.5 times the height H1 as measured at a position spaced a distance of ten times the height H1 apart from the edge of thelens portion 40A, for example. The diffusion (divergence) of the light beam S is set by adjusting a distance d from a light-emitting surface of a light-emittingcore 3A to the edge of the light-emittinglens portion 40A, and the radius of curvature R of thecurved lens surface 41A of the light-emittinglens portion 40A as appropriate. In this manner, the emitted light beams S are diffused in the vertical direction. This accommodates warpage or distortion, if any, in the optical waveguide W1 to achieve proper optical transmission. It should be noted that the emitted light beam S in the first preferred embodiment is diffused also in a horizontal direction (in a direction perpendicular to the height or vertical direction). - As shown in
FIG. 2 , the optical waveguide W1 in the form of the rectangular frame is provided along the rectangular shape of the periphery of the display screen of therectangular display 11 of atouch panel 10 so as to surround the display screen of therectangular display 11. In the predetermined portion F provided at an outer end edge of the light-emitting optical waveguide section A, a light source (not shown) such as a light-emitting element is connected to ends of thecores 3A. In the predetermined portion G provided at an outer end edge of the light-receiving optical waveguide section B, a detector (not shown) such as a light-receiving element is connected to ends of thecores 3B. InFIG. 2 , thecores cores FIG. 1A . Also, the number ofcores FIG. 2 for ease of understanding. - In the light-emitting optical waveguide section A, light beams S emitted from the light source travel through the
cores 3A, and exit the end surfaces of thecores 3A. Thereafter, the light beams S pass through and exit thelens portion 40A at the edge of the overcladding layer 4 in front of the end surfaces of thecores 3A. At this time, the diffusion of the light beams S in the vertical direction is optimized as described above by refraction resulting from thelens surface 41A (with reference toFIG. 1C ) of thelens portion 40A. Then, the light beams S travel over the display screen of the display 11 (with reference toFIG. 2 ) toward the light-receiving optical waveguide section B. - In the light-receiving optical waveguide section B, on the other hand, the light beams S having traveled over the display screen of the display 11 (with reference to
FIG. 2 ) enter thelens surface 41B (with reference toFIG. 1C ) of thelens portion 40B at the edge of the overcladding layer 4, and are narrowed down and converged in the vertical direction by refraction resulting from thelens surface 41B of thelens portion 40B. Then, while being converged, the light beams S travel from the end surfaces of thecores 3B into thecores 3B, and are detected by the detector (not shown). - Such transmission of the light beams S is done in the optical waveguide W1 shown in
FIG. 2 . Thus, as shown inFIG. 2 , the light beams S diffuse gradually in the vertical direction (upwardly as seen inFIG. 2 ) over the display screen of thedisplay 11 of thetouch panel 10 as the light beams S travel from the light-emitting optical waveguide section A toward the light-receiving optical waveguide section B. In that state, the light beams S travel in a lattice form (although only some of the light beams S forming the lattice are shown inFIG. 2 for ease of understanding). This enables the light-receivinglens portion 40B to lie within a light-receiving region if warpage or distortion occurs in the optical waveguide W1. Thus, when a portion of the display screen of thedisplay 11 is touched with a finger, the position of the portion touched with the finger is accurately detected. - Next, an example of a method of manufacturing the optical waveguide W1 will be described with reference to
FIGS. 3A to 3D andFIGS. 4A to 4C which mainly illustrate theopposed lens portions FIGS. 1A to 1C and a peripheral portion thereof. - First, a
base 1 of a flat shape (with reference toFIG. 3A ) for use in the manufacture of the optical waveguide W1 is prepared. Examples of a material for the formation of thebase 1 include glass, quartz, silicon, resin, and metal. Thebase 1 has a thickness, for example, in the range of 20 μm to 5 mm. - Then, as shown in
FIG. 3A , the undercladding layer 2 is formed on a surface of thebase 1. Examples of a material for the formation of theunder cladding layer 2 include thermosetting resins and photosensitive resins. When a thermosetting resin is used, a varnish prepared by dissolving the thermosetting resin in a solvent is applied to thebase 1, and a layer of the applied varnish is then heated to thereby form the undercladding layer 2. When a photosensitive resin is used, on the other hand, a varnish prepared by dissolving the photosensitive resin in a solvent is applied to thebase 1, and a layer of the applied varnish is then exposed to irradiation light such as ultraviolet light to thereby form the undercladding layer 2. The undercladding layer 2 has a thickness, for example, in the range of 5 to 70 μm. - Next, as shown in
FIG. 3B , thecores under cladding layer 2 by a photolithographic method. Preferably, a photosensitive resin excellent in patterning characteristics is used as a material for the formation of thecores cores cores - The material for the formation of the
cores under cladding layer 2 described above and the overcladding layer 4 to be described below (with reference toFIG. 1C ). The adjustment of the refractive index may be made, for example, by adjusting the selection of the types of the materials for the formation of theunder cladding layer 2, thecores cladding layer 4, and the composition ratio thereof. - Then, as shown in
FIG. 3C , a photosensitive resin to be formed into the overcladding layer 4 is applied to the surface of theunder cladding layer 2 so as to cover thecores photosensitive resin layer 4 a (uncured). An example of the photosensitive resin to be formed into the overcladding layer 4 includes a photosensitive resin similar to that for theunder cladding layer 2. - Then, as shown in
FIG. 3D , amold 20 for press molding the overcladding layer 4 into the shape of the rectangular frame is prepared. Thismold 20 is made of a material (for example, quartz) permeable to irradiation light such as ultraviolet light, and includes a cavity having amold surface 21 complementary in shape to the surface of the overcladding layer 4 including thelens portions - Then, as shown in
FIG. 4A , themold 20 is pressed against thephotosensitive resin layer 4 a so that the mold surface 21 (the cavity) of themold 20 is positioned in a predetermined location relative to thecores photosensitive resin layer 4 a into the shape of the overcladding layer 4. Next, thephotosensitive resin layer 4 a is exposed to irradiation light such as ultraviolet light through themold 20 in that state. Thereafter, a heating treatment is performed. The exposure and the heating treatment are carried out in a manner similar to those performed in the method for the formation of theunder cladding layer 2 described with reference toFIG. 3A . - Thereafter, the
mold 20 is removed, as shown inFIG. 4B . This provides the overcladding layer 4 in the form of a rectangular frame which includes thelens portions cladding layer 4 has a thickness (as measured from the surface of the under cladding layer 2) generally in the range of 50 to 2000 μm. - Thereafter, as shown in
FIG. 4C , the undercladding layer 2 together with thebase 1 is cut into the shape of a rectangular frame by punching using a blade and the like. In this manner, the optical waveguide W1 in the form of the rectangular frame which includes the undercladding layer 2, thecores cladding layer 4 is manufactured on the surface of thebase 1. The optical waveguide W1 is used after being stripped from the base 1 (with reference toFIG. 1C ). -
FIG. 5 shows an optical waveguide W2 for a touch panel according to a second preferred embodiment. In the optical waveguide W2 according to the second preferred embodiment, the height H2 of the light-receivinglens portion 40B is greater than the height H1 of the light-emittinglens portion 40A. - A light beam S emitted from the light-emitting
lens portion 40A is adapted to be collimated, as shown inFIG. 5 , rather than to diffuse in the vertical direction. It should be noted that the emitted light beam S in the second preferred embodiment is diffused in a horizontal direction (in a direction perpendicular to the height or vertical direction). Other parts of the second preferred embodiment are similar to those of the first preferred embodiment. Like reference numerals and characters are used to designate parts similar to those of the first preferred embodiment. - Preferably, the height H2 of the light-receiving
lens portion 40B satisfies the following relations (4) to (6). -
H2=H1×(1+a×L/100) (4) -
0<a≦5 (5) -
H1=M (6) - where H1 and H2 are in millimeters, L is a distance between edges of the light-emitting and light-receiving
lens portions lens portion 40A as measured at the edge of the light-receivinglens portion 40B in millimeters. Specifically, for example, when the distance L between the edges of the light-emitting and light-receivinglens portions lens portion 40A, the height H2 of the light-receivinglens portion 40B is preferably greater than the height H1 of the light-emittinglens portion 40A so as to be greater than 1.0 times the height H1 and to be not greater than 1.5 times the height H1. - In the second preferred embodiment, light beams S emitted from the
lens portion 40A of the light-emitting optical waveguide section A are not diffused in the vertical direction but are collimated by refraction resulting from thelens surface 41A of thelens portion 40A. Also, the height H2 of the light-receivinglens portion 40B is greater than the height H1 of the light-emittinglens portion 40A (the vertical width M of the collimated light beam S). This enables the light-receivinglens portion 40B to lie within the light-receiving region if warpage or distortion occurs in the optical waveguide W2. Thus, the position of a portion of the display screen of thedisplay 11 touched with a finger is accurately detected in the touch panel 10 (with reference toFIG. 2 ). - In the first and second preferred embodiments, the photosensitive resin is used to form the under
cladding layer 2. However, in place of the photosensitive resin, a resin film functioning as the undercladding layer 2 may be prepared and used as it is as the undercladding layer 2. Alternatively, in place of theunder cladding layer 2, a substrate with a metal film formed on the surface thereof may be used as a body having a surface on which thecores - Although the optical waveguides W1 and W2 are in the form of the rectangular frame in the first and second preferred embodiments, each of the optical waveguides W1 and W2 in the form of the rectangular frame may be divided into the two L-shaped optical waveguide sections constituting each of the optical waveguides W1 and W2. A manufacturing method thereof may include the step of cutting the under
cladding layer 2 together with thebase 1 into two L-shaped sections in place of the step of cutting the undercladding layer 2 together with thebase 1 into the shape of the rectangular frame. Further, at least one of the two L-shaped optical waveguide sections may be subdivided into linear optical waveguide sections constituting the at least one section. - Also, the optical waveguides W1 and W2 in the first and second preferred embodiments are used after being stripped from the
base 1. However, the optical waveguides W1 and W2 still provided on the surface of thebase 1 may be used without being stripped therefrom. - Next, an inventive example of the pre sent invention will be described in conjunction with a comparative example. It should be noted that the present invention is not limited to the inventive example.
- A ray tracing simulation was performed using optical simulation software known as “LIGHTTOOLS” available from Optical Research Associates. Settings of a simulation model of a light-emitting optical waveguide section were as follows:
- Over cladding layer: a refractive index of 1.50; a thickness of 1 mm; and a lens portion height of 1 mm.
- Cores: a refractive index of 1.57; a thickness of 50 μm; and a width of 15 μm.
- Under cladding layer: a refractive index of 1.50; and a thickness of 15 μm.
- Distance of 4.04 mm from light-emitting surfaces of the cores to an edge of a lens portion.
- In the simulation model, when the radius of curvature R of a curved lens surface of the lens portion was 1.4 mm (when
Sample 1 having R=1.4 mm was prepared), light beams emitted from the curved lens surface were not diffused in a vertical direction but were collimated (so as to have a vertical width of 1 mm). When the radius of curvature R was 1.5 mm and 1.6 mm (whenSample 2 having R=1.5 mm and Sample 3 having R=1.6 mm were prepared), light beams emitted from the curved lens surface were diffused in the vertical direction. The vertical widths of the light beams inSamples 2 and 3 were 1.2 mm and 1.5 mm, respectively, as measured at a position spaced a distance of 10 mm apart from the edge of the lens portion. - A light-receiving surface (having a height of 1 mm and a width of 20 mm) corresponding to a light-receiving lens portion was set at a position 100 mm ahead of the edge of the lens portion in the simulation model.
- [Optical Transmission Loss Resulting from Warpage]
- The optical transmission loss at the light-receiving surface was simulated, while the lens portion in the simulation model was inclined upwardly and downwardly with respect to a horizontal direction (with an inclination angle of 0 degrees). The lens portion was inclined upwardly and downwardly to an angle of six degrees in steps of one degree.
- The result was that the optical transmission loss increased as the inclination angle increased in
Samples 1 to 3. However,Sample 1 in which the emitted light beams were collimated light beams was smaller in the increase in optical transmission loss thanSamples 2 and 3 in which the emitted light beams were diffused. - [First Optical Transmission Loss Resulting from Vertical Misregistration]
- The simulation model was held in a horizontal position. In this state, the optical transmission loss at the light-receiving surface was simulated, while the light-receiving surface was moved upwardly. The light-receiving surface was moved upwardly to a distance of 1.0 mm in steps of 0.2 mm.
- The result was that the optical transmission loss increased as the amount of movement of the light-receiving surface increased in
Samples 1 to 3. However,Sample 1 in which the emitted light beams were collimated light beams was smaller in the increase in optical transmission loss thanSamples 2 and 3 in which the emitted light beams were diffused. - The result shows that an optical waveguide for a touch panel in which emitted light beams are diffused in the vertical direction is capable of causing light beams emitted from the light-emitting lens portion to sufficiently enter a light-receiving optical waveguide section if warpage or distortion occurs in the optical waveguide itself.
- [Second Optical Transmission Loss Resulting from Vertical Misregistration]
- The simulation model in
Sample 1 in which the emitted light beams were collimated light beams was held in a horizontal position, and the light-receiving surface was moved 0.1 mm upwardly. In this state, the illuminance of light beams received by the light-receiving surface was simulated, while the height (vertical width) of the light-receiving surface was increased from 1.0 mm to 2.0 mm in steps of 0.2 mm. Also, the light-receiving surface was moved 0.1 mm downwardly. In this state, the illuminance of light beams received by the light-receiving surface was simulated, while the height of the light-receiving surface was increased in a similar manner. - The result was that the illuminance of the light beams received by the light-receiving surface increased as the height of the light-receiving surface increased in either case.
- The result shows that an optical waveguide for a touch panel in which the height of the light-receiving lens portion is greater than that of the light-emitting lens portion is capable of causing light beams emitted from the light-emitting lens portion to sufficiently enter the light-receiving optical waveguide section if warpage or distortion occurs in the optical waveguide itself.
- Although specific forms of embodiments of the instant invention have been described above and illustrated in the accompanying drawings in order to be more clearly understood, the above description is made by way of example and not as a limitation to the scope of the instant invention. It is contemplated that various modifications apparent to one of ordinary skill in the art could be made without departing from the scope of the invention.
- The optical waveguide for a touch panel is applicable to an optical waveguide for use as a detection means (a position sensor) for detecting a finger touch position and the like in a touch panel.
Claims (5)
1. An optical waveguide for a touch panel, comprising:
cores; and
an over cladding layer which covers the cores,
the optical waveguide configured to be disposed along the periphery of a display screen of a display of a touch panel,
wherein the cores includes a light-emitting core for emitting a light beam and a light-receiving core for receiving the light beam,
wherein the light-emitting core has an end surface positioned on one side of the display screen of the display,
wherein the light-receiving core has an end surface positioned on the other side of the display screen of the display,
wherein the over cladding layer includes a first edge covering the end surface of the light-emitting core and configured in the form of a light-emitting lens portion having an outwardly-bulging arcuately curved surface as seen in vertical sectional view, and a second edge covering the end surface of the light-receiving core and configured in the form of a light-receiving lens portion having an outwardly-bulging arcuately curved surface as seen in vertical sectional view, and
wherein the light-emitting lens portion has one of the following configurations: a first configuration in which a light beam emitted from the light-emitting lens portion is adapted to diffuse in the direction of the height of the light-emitting lens portion; and a second configuration in which the height of the light-emitting lens portion is less than the light of the light-receiving lens portion.
2. The optical waveguide according to claim 1 , wherein the first configuration of the light-emitting lens portion satisfies
M=H1×(1+a×L/100)
0<a≦5
H1=H2
M=H1×(1+a×L/100)
0<a≦5
H1=H2
where H1 is the height of the light-emitting lens portion in millimeters, H2 is the height of the light-receiving lens portion in millimeters, L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters, and M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters.
3. The optical waveguide according to claim 1 , wherein the second configuration of the light-emitting lens portion satisfies
H2=H1×(1+a×L/100)
0<a≦5
H1=M
H2=H1×(1+a×L/100)
0<a≦5
H1=M
where H1 is the height of the light-emitting lens portion in millimeters, H2 is the height of the light-receiving lens portion in millimeters, L is a distance between edges of the light-emitting and light-receiving lens portions in millimeters, and M is a vertical width of a light beam emitted from the light-emitting lens portion as measured at the edge of the light-receiving lens portion in millimeters.
4. The optical waveguide according to claim 1 , wherein the vertical width of a light beam emitted from the light-emitting lens portion is set based on a distance from a light-emitting surface of the light-emitting core to the edge of the light-emitting lens portion, and the radius of curvature of the arcuately curved surface of the light-emitting lens portion.
5. The optical waveguide according to claim 2 , wherein the vertical width of a light beam emitted from the light-emitting lens portion is set based on a distance from a light-emitting surface of the light-emitting core to the edge of the light-emitting lens portion, and the radius of curvature of the arcuately curved surface of the light-emitting lens portion.
Applications Claiming Priority (2)
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JP2010183230A JP2012043136A (en) | 2010-08-18 | 2010-08-18 | Optical waveguide for touch panel |
JP2010-183230 | 2010-08-18 |
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US20120045170A1 true US20120045170A1 (en) | 2012-02-23 |
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US13/207,926 Abandoned US20120045170A1 (en) | 2010-08-18 | 2011-08-11 | Optical waveguide for touch panel |
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US20140362053A1 (en) * | 2008-06-19 | 2014-12-11 | Neonode Inc. | Light-based touch surface with curved borders |
US9158416B2 (en) | 2009-02-15 | 2015-10-13 | Neonode Inc. | Resilient light-based touch surface |
US9411430B2 (en) | 2008-06-19 | 2016-08-09 | Neonode Inc. | Optical touch screen using total internal reflection |
WO2018106176A1 (en) * | 2016-12-07 | 2018-06-14 | Flatfrog Laboratories Ab | An improved touch device |
US11669210B2 (en) | 2020-09-30 | 2023-06-06 | Neonode Inc. | Optical touch sensor |
US11893189B2 (en) | 2020-02-10 | 2024-02-06 | Flatfrog Laboratories Ab | Touch-sensing apparatus |
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- 2011-08-11 CN CN2011102319446A patent/CN102375179A/en active Pending
- 2011-08-11 KR KR1020110079976A patent/KR20120017403A/en not_active Application Discontinuation
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- 2011-08-11 US US13/207,926 patent/US20120045170A1/en not_active Abandoned
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Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
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US20140362053A1 (en) * | 2008-06-19 | 2014-12-11 | Neonode Inc. | Light-based touch surface with curved borders |
US8989536B2 (en) * | 2008-06-19 | 2015-03-24 | Neonode Inc. | Light-based touch surface with curved borders |
US9335867B2 (en) | 2008-06-19 | 2016-05-10 | Neonode Inc. | Light-based touch surface with curved borders |
US9411430B2 (en) | 2008-06-19 | 2016-08-09 | Neonode Inc. | Optical touch screen using total internal reflection |
US9158416B2 (en) | 2009-02-15 | 2015-10-13 | Neonode Inc. | Resilient light-based touch surface |
US9811163B2 (en) | 2009-02-15 | 2017-11-07 | Neonode Inc. | Elastic touch input surface |
US20130048834A1 (en) * | 2011-08-29 | 2013-02-28 | Nitto Denko Corporation | Input device |
US20130077918A1 (en) * | 2011-09-26 | 2013-03-28 | Nitto Denko Corporation | Input device |
WO2018106176A1 (en) * | 2016-12-07 | 2018-06-14 | Flatfrog Laboratories Ab | An improved touch device |
US10282035B2 (en) | 2016-12-07 | 2019-05-07 | Flatfrog Laboratories Ab | Touch device |
US11893189B2 (en) | 2020-02-10 | 2024-02-06 | Flatfrog Laboratories Ab | Touch-sensing apparatus |
US11669210B2 (en) | 2020-09-30 | 2023-06-06 | Neonode Inc. | Optical touch sensor |
Also Published As
Publication number | Publication date |
---|---|
JP2012043136A (en) | 2012-03-01 |
CN102375179A (en) | 2012-03-14 |
KR20120017403A (en) | 2012-02-28 |
TW201219866A (en) | 2012-05-16 |
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